U:\2021\BM210482_IBo_Waihi_North_Project\Documents\WNP_Freshwater_Report_May_2022\FINAL_Freshwater_Report_FOR DELIVERY_June 2022\FINAL DELIVERED 17 JUNE 2022\WAI-985-000-REP-LC-0007_Rev0_Freshwater_20220621_FINAL.docx Maximum 28.7 25.30 26.05 27.31 27.75 27.51 27.07 n 168 182 182 182 182 182 182 Table 44: Number of records from OGNZL monitoring sites within the Ohinemuri River over the critical summer period (1 November 2019 to 30 April 2020) where daily temperature CRI has exceeded recommended temperature thresholds 20⁰C to 25⁰C. Site locations shown in Figure 14. Sample site Temperature (CRI) exceedance OC2A OC2B OH3 OH5 OH1 OH6 > 25°C 1 2 9 20 16 11 > 24°C 3 10 24 39 33 30 > 23°C 17 27 42 64 67 43 > 22°C 41 58 71 85 88 60 > 21°C 78 86 91 102 103 84 > 20°C 93 103 111 119 118 97 n 182 182 182 182 182 182 Table 45: Number of recorded daily temperature CRI differences between upstream and downstream monitoring sites over the critical summer period (November to April inclusive inclusive) in the Ohinemuri River at Waihi. Site locations shown in Figure 14. CRI Temperature change OC2B and OH5 OC2B and OH1 OC2B and OH6 OH3 and OH5 OH3 and OH1 OH3 and OH6 OH5 and OH6 > 3°C 1 0 2 0 0 1 0 > 2°C 22 11 22 0 0 7 1 > 1°C 107 100 66 47 26 46 8 n 182 182 182 182 182 182 182 Of note from these results is the comparison between OH3 and OH5 during the critical summer period. These sites are virtually on the same stretch of river (or a similar part of the river), less than 1 km apart, and with the treated water discharge between them. While there are several occasions where the temperature increase is >1⁰C during the summer period, there are none >2⁰C. 20.5.5 Effects of temperature on ecological values The all-year median in-river temperature was below the critical thermal thresholds and lower than the optimum growth temperatures for most species (Figure 31). Median temperature during the critical summer period is at the lowland river threshold while maximum temperatures are occasionally above the recommended thermal threshold. However, we also note that the in-river
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